If this is your first visit, be sure to check out the FAQ by clicking the link above. Here’s why kiln drying is only a first step in the moisture content process: At any step of the process after the kiln-transportation, manufacturing, storage or installation-it is possible for wood, even manufactured wood flooring, to lose additional moisture (in a dry environment) or re-absorb ambient moisture (in a humid environment) and have its moisture content level, and possibly even its dimensions, change again.
The main advantage of the solar kiln is the simplicity to construct and operate. Heart shakes tend to get larger as the wood dries so it is best to remove any heart shakes or defects at the centre of the log by cutting either side of the defects to yield split-free pieces which are likely to dry without further loss. I like to build my pile 4′ wide and place the cross bunks every 2′. When I first started drying lumber 30-plus years ago, the stickers were typically placed on 2′ centers, but over time I have switched to placing the sticks on 1′ centers for lumber that is 4/4 to 6/4 thick, although I still sticker my thicker lumber on 2′ centers.
Logs and cants can be placed in a kiln for what seems to be an adequate period of time, then be removed and machined at a moisture content above the fiber saturation point. With difficult fine grained slow drying wood, such as Cherry or Apple, more protection is required. Since we are planning to use these resources, the idea is to air-dry the lumber until it will give up no more moisture without assistance, and then look at different ways to complete the drying process. Does black walnut cut for 3/4″ flooring need to be kiln dried if it is saw cut at 1″-1/8 We will let it sit air drying for one year.
Conventional timber drying methods have peaked their maturity levels after decades of optimizing research. Agreed – it’s one thing to suck water out of the air, quite another to suck it out of the middle of a piece of wood. As you can imagine, when discussing the manner in which wood dries, a bit of science is involved. In-line and in-kiln moisture measurement systems help to determine when the wood has reached optimal MC levels.
Accurate control in the Solarkilns chamber of humidity and temperature allow sensitive products to be dried with optimal control during critical stages of the drying process which can eliminate degraded product. One of the big advantages of being a woodturner is that you can use green or part seasoned wood without waiting years for it to dry – provided you know what you are doing. We made a large kiln for a Boy Scout camp using the body from an old dairy delivery truck. The percentage of water in the wood may get as low as 5% but there always will be some water left in there. This kiln captures the energy needed to dry wood from the water in the wood itself.
A selection of sizes from three to six inches in diameter for wood stoves and an inch or so larger for furnaces will probably serve you well. My first kiln was a solar one, and it worked very well from spring through fall, with the added benefit of lower energy costs. You may obtain more detailed information on this subject from USDA Agriculture Handbooks Number 188, Dry Kiln Schedules for Commercial Woods.
With VacDry vacuum kiln drying, wood comes out of the kiln looking just as it did going in. The cherry is bright. Wood seasoned via the compartmental process remains in a single building where it is subjected to a program of varying conditions until the moisture content is removed. It is a more passive method that relies on ambient conditions of the surrounding environment to extract moisture from wood. Yes, all the dehumidifier does is to suck the water out of the air, but that dry air is what dries the wood… ALWAYS.
Under the right conditions, like a very arid day with too much wind, you can ruin a freshly stickered pack of lumber in a very short time by drying the surface so fast it surface-checks and honeycombs the lumber at the same time. Periodically sampling the actual moisture content of the lumber in the kiln ensures that changes in temperature and humidity settings keep the lumber drying at the maximum safe rate schedule.
Adjust the baffles to accommodate size variations in lumber packages in the kiln and to account for the lumber shrinkage that occurs during the drying process. We manufacture a full and comprehensive range of wood drying kilns for all sectors of the timber industry, this includes softwood and hardwood sawmills, pallet producers, fencing manufacturers and more recently kilns to dry logs and wood chips for the Biomass market.